1. Field of the Invention
This invention relates to an improved combination of a power transmission belt that is adapted to be operated in an endless path and a tensioner for such belt as well as to the tensioner per se and to methods of making and operating such combination and the tensioner therefor.
2. Prior Art Statement
It is known in the art to provide a combination of a power transmission belt that is adapted to be operated in an endless path and a tensioner for the belt, the tensioner comprising a support means fixed relative to the belt, a belt engaging means carried by the support means and being movable relative thereto, and biasing means operatively associated with the support means and the belt engaging means urging the belt engaging means relative to the support means in a belt tensioning direction and against the belt with a force to tension the belt.
Examples of combinations of the above mentioned type are provided in the following five United States Patents:
(1) U.S. Pat. No. 3,413,866--Ford PA1 (2) U.S. Pat. No. 4,108,013--Sragal PA1 (3) U.S. Pat. No. 4,145,934--Sragal PA1 (4) U.S. Pat. No. 4,151,756--Binder et al PA1 (5) U.S. Pat. No. 4,249,425--Watson PA1 (6) U.S. Pat. No. 3,623,377--Lewis et al PA1 (7) U.S. Pat. No. 4,024,772--Kumm
It appears from item (1) above that a tension spring urges an idler pulley in tensioning engagement against a belt.
It appears from item (2) above that a compression spring urges an idler pulley in tensioning engagement against a belt.
It appears from item (3) above that a leaf spring urges an idler pulley in tensioning engagement against a belt.
It appears from item (4) above that a plurality of bimetal dish-shaped springs or spring washers are disposed in various stacked relations thereof and urge an idler pulley in tensioning engagement against a belt.
It appears from item (5) above that pneumatic means is adapted to threadedly adjust an idler pulley rod of a belt tensioner wherein a pair of dish-shaped springs or spring washers urge the idler pulley in tensioning engagement against a belt.
It is also known to provide variable speed pulleys.
For example, see the following two United States Patents:
It appears that the variable speed pulley of item (6) above increases its effective diameter as the speed of rotation thereof increases, the pulley construction being adapted for operating on the opposed sides of a V-belt construction.
It appears that the variable speed pulley of item (7) above is adjustable under the force of a piston and cylinder arrangement and is adapted to operate on the bottom driving surface of a belt construction or on the opposed sides of a V-belt construction.